The commonly used model that uses leaf area and leaf dry weight to calculate the leaf area is highly sensitive to leaf area, and the small specific leaf area simulation error will lead to larger leaf area index simulation errors, which will greatly affect canopy photosynthesis. The accuracy of the role and dry matter production simulations, in turn, will affect the accuracy of the simulation of the leaf area index, thus creating a vicious circle. Therefore, the direct determination of the leaf area meter is currently a more appropriate method.
In simulating the leaf area of ​​crops, in addition to the increase in leaf area, the stoppage of leaf area and the reduction of leaf area caused by crop maturation or pruning also require simulations. However, the factors that control the cessation of leaf growth are still unclear. Decreases in leaf area meter measurements may begin after a certain critical period of development. In actual production, the leaf area is subject to artificial regulation, and many cultivation and management measures such as pruning, topping, and old leaves can reasonably adjust the leaf area.
A leaf area meter was used to calculate the area of ​​lateral branch leaves. The number of leaves on the side branches was mainly affected by temperature, but the leaf extension rate, extension duration, etc. were susceptible to the cultivation and management measures such as fertilizer, water supply conditions, pruning methods, planting density, and different crop growth periods. The influence of temperature radiation, and the measurement of leaf area meter at the same time is also subject to certain differences between China's cultivation methods and foreign countries. Simply estimating the leaf area based on leaf number is too empirical to be applied in other places.
China's greenhouse Poinsettia most of the organic substrate cultivation, the root environment is more difficult to control, in the growth process, there will be more or less water, fertilizer deficiency situation. Therefore, under the current level of production in our country, the numerical analysis using the leaf area meter than the leaf area changes with the growth period is often broken by the water and fertilizer deficits occurring in the crop production process, thus bringing the simulation of the leaf area. difficult.